Space Sunshield Dummies' Guide

* There are 22 "hybrid" rocket motors onboard, constructed by Damian Hall and his team.  Hybrid rocket motors are made of nitrous oxide and rubber. They are homemade and each one weighs 88 pounds (40 kilograms).

* Before ignition, a thin layer of rubber piping that divides the nitrous and the main rubber cylinder is heated to 968 degrees Fahrenheit (520 degrees Celsius).  It melts, allowing the heated nitrous to come into contact with the rubber, forming a chemical reaction that creates the thrust.

* The rocket will burn 300 pounds of rocket fuel.

* The motors fire for 4 1/2 seconds in two stages — the first stage fires four of the motors, the second the remaining three.

* Each motor was planned to burn for four-and-a-half seconds each, accelerating the rocket to a height of 1,000 feet.  The first stage would then fall away, and booster motors will take over, powering it to its full speed of 500 mph and an altitude of 8,000 feet.

* It produces 10 tons of thrust, the equivalent of a jet fighter.

* In terms of net explosive quantity — a measurement of explosive power — the rocket carries 234 pounds (106 kilograms) of NEQ.

* The rocket itself is made of trilite aluminum used in rock music staging, plywood rings and covered in sheet aluminum.  Damian Hall described it as 90 percent air. Total weight is around 1,433 pounds (650 kilograms), although it was heavier than expected at launch.

* When the rocket was launched, it reached a height of 2,500 feet, although it was designed to reach around 8,000 feet.  By the time it reached its zenith it was only traveling at around 100-120 mph — far less than what was hoped to be its full speed of 450 mph. 

Why the Rocket Crashed

One of the four main motors failed on lift-off.  By itself this should not have been a problem.  However, the second stage motors took around two seconds longer than expected to come up to pressure after the rocket team initiated the second stage radio uplink command for second stage ignition. 

Damian Hall believes that the delayed motor ignition was a result of low oxidizer pressure. During this period, the oxidizer was progressively getting cooler.  A cool oxidizer means less thrust and increased time from ignition to operation.

Given the rocket's slow first stage ascent and the delayed second stage boost the rocket came to a standstill in mid air and tail-slid a couple of feet. This fooled the onboard computers into thinking the rocket was at its apogee — so the flight computers fired the escape tower separation motors located at the nose of the rocket. These motors serve to separate the payload section from the main booster with the rocket coasting on it's side, at apogee, several thousand feet up.

Unfortunately, just at the moment the escape tower motors fire, the second stage boost motors came up to pressure providing four tons of thrust — working against the escape tower 'separation motors'. This resulted in no separation of the payload section and without separation, there is no recovery.